iOS开发中使用Picker View实现一个点菜应用的UI示例

//
//  yyviewcontroller.m
//  06-简单选菜系统的实现
//
//  created by apple on 14-6-5.
//  copyright (c) 2014年 itcase. all rights reserved.
//

#import "yyviewcontroller.h"

//遵守数据源和代理协议
@interface yyviewcontroller ()<uipickerviewdatasource,uipickerviewdelegate>
/**
 *  水果
 */
@property (strong, nonatomic) iboutlet uilabel *fruitlab;
/**
 *  主菜
 */
@property (strong, nonatomic) iboutlet uilabel *staplelab;
/**
 *  饮料
 */
@property (strong, nonatomic) iboutlet uilabel *drinklab;
/**
 *  保存所有的数据
 */
@property(nonatomic,strong)nsarray *foods;
@property (weak, nonatomic) iboutlet uipickerview *pickerview;
- (ibaction)randomfood:(id)sender;

@end

@implementation yyviewcontroller

- (void)viewdidload
{
    [super viewdidload];
   
    //在这里设置下方数据刷新部分的初始显示
    for (int component = 0; component<self.foods.count; component++) {
        [self pickerview:nil didselectrow:0 incomponent:component];
    }
}

#pragma mark-使用懒加载，把数据信息加载进来
-(nsarray *)foods
{
    if (_foods==nil) {
        nsstring *fullpath=[[nsbundle mainbundle]pathforresource:@"foods.plist" oftype:nil];
        nsarray *arraym=[nsarray arraywithcontentsoffile:fullpath];
        _foods=arraym;
    }
    return _foods;
}

#pragma mark-处理随机按钮的点击事件
- (ibaction)randomfood:(id)sender {
   
    // 让pickerview主动选中某一行
    // 让pickerview选中incomponent列的row行
    //    [self.pickerview selectrow:1 incomponent:0 animated:yes];
   
    /*
     [self.pickerview selectrow: arc4random() % 12 incomponent:0 animated:yes];
     [self.pickerview selectrow: arc4random() % 15 incomponent:1 animated:yes];
     [self.pickerview selectrow: arc4random() % 10 incomponent:2 animated:yes];
     */
   
    //    [self.foods objectatindex:0]; == self.foods[0];
    //    [self.foods[0] count];
   
    /*
     // 根据每一列的元素个数生成随机值
     [self.pickerview selectrow: arc4random() % [self.foods[0] count] incomponent:0 animated:yes];
     [self.pickerview selectrow: arc4random() % [self.foods[1] count] incomponent:1 animated:yes];
     [self.pickerview selectrow: arc4random() % [self.foods[2] count] incomponent:2 animated:yes];
     */
   
    //设置一个随机数
    for (int component=0; component<self.foods.count; component++) {
        //获取当前列对应的数据元素的个数
        int total=[self.foods[component] count];
        //根据每一列的总数生成随机数（当前生成的随机数）
        int randomnumber=arc4random()%total;
       
        //获取当前选中的行（上一次随机后移动到的行）
        int oldrow=[self.pickerview selectedrowincomponent:0];
       
        //比较上一次的行号和当前生成的随机数是否相同，如果相同的话则重新生成
        while (oldrow==randomnumber) {
                randomnumber=arc4random()%total;
        }
       
        //让pickerview滚动到指定的某一行
        [self.pickerview selectrow:randomnumber incomponent:component animated:yes];
        //模拟，通过代码选中某一行
        [self pickerview:nil didselectrow:randomnumber incomponent:component];
    }
}

#pragma mark- 设置数据
//一共多少列
-(nsinteger)numberofcomponentsinpickerview:(uipickerview *)pickerview
{
    return self.foods.count;
}

//每列对应多少行
-(nsinteger)pickerview:(uipickerview *)pickerview numberofrowsincomponent:(nsinteger)component
{
    //1.获取当前的列
    nsarray *araym= self.foods[component];
    //2.返回当前列对应的行数
    return araym.count;
}

//每列每行对应显示的数据是什么
-(nsstring *)pickerview:(uipickerview *)pickerview titleforrow:(nsinteger)row forcomponent:(nsinteger)component
{
    //1.获取当前的列
    nsarray *araym= self.foods[component];
    //2.获取当前列对应的行的数据
    nsstring *name=araym[row];
    return name;
}

#pragma mark-设置下方的数据刷新
// 当选中了pickerview的某一行的时候调用
// 会将选中的列号和行号作为参数传入
// 只有通过手指选中某一行的时候才会调用
-(void)pickerview:(uipickerview *)pickerview didselectrow:(nsinteger)row incomponent:(nsinteger)component
{
    //获取对应列，对应行的数据
    nsstring *name=self.foods[component][row];
    //赋值
    if (0==component) {
        self.fruitlab.text=name;
    }else if(1==component)
    {
        self.staplelab.text=name;
    }else
        self.drinklab.text=name;
}

#pragma mark-隐藏状态栏
-(bool)prefersstatusbarhidden
{
    return yes;
}
@end